1. Field of the Invention
This invention relates to a shaft drive apparatus for a rear wheel in a motorized two-wheeled vehicle such as a motorcycle or the like.
2. Description of the Prior Art
An example of a known shaft-drive apparatus is shown in FIG. 1 and comprises, for instance, an output shaft b connected to an internal combustion engine a through a propeller shaft f extending through the interior of a rear fork d and a torque damper e to an input shaft c of a bevel gear mechanism connected to a rear wheel. It has been usual with this type of drive that the damper e is lubricated with oil g stored in the rear fork d as shown in the Figure. Consequently, certain problems can result, such as the oil being moved forwards along the fork d because of an inclination of the rear fork. The oil g then is introduced into a boot h provided on the front end portion of the rear fork d. This changes the oil level, which is undesirable. Additionally, the oil can leak from the boot h.